Drilling vs Doing

How does one become proficient at doing something? Should you drill or perform the activity real time. For me personally, I prefer to just do it. When I played soccer as a youth, we would scrimmage to prepare for the game. When I boxed,sparring was the main method of preparation (same for kickboxing, judo, etc.). I never really did a lot of drills because I felt that after a certain point they created a pattern to how one moves and reacts. I always wanted to be adaptable, so I would just do. This may not work for all, but it is my believe. I want to be like water and be adaptable.